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The prompt identification of faults responsible for moderate‐to‐large earthquakes is fundamental for understanding the likelihood of further, potentially damaging events. This is increasingly challenging when the activated fault is an offshore buried thrust, where neither coseismic surface ruptures nor GPS/InSAR deformation data are available after an earthquake. We show that on 9 November 2022, an Mw 5.5 earthquake offshore Pesaro ruptured a portion of the buried Northern Apennines thrust front (the Cornelia thrust system [CTS]). By post‐processing and interpreting the seismic reflection profiles crossing this thrust system, we determined that the activated fault (CTS) is an arcuate 30‐km‐long, NW‐SE striking, SW dipping thrust and that older structures at its footwall possibly influenced its position and geometry. The activation of adjacent segments of the thrust system is a plausible scenario that deserves to be further investigated to understand the full earthquake potential of this offshore seismogenic source. Plain Language Summary: The Northern Apennines chain is characterized by thrust faults running from the Po Plain to the Adriatic Sea on the northeastern side of peninsular Italy. These thrusts are buried below ≈2,000 m cover of Plio‐Pleistocene deposits. Controversies arose about these thrust faults' activity and earthquake potential based on their hidden geological signature and the scanty seismicity that could be associated with them. The earthquake (magnitude 5.5) that occurred on 9 November 2022, offshore Pesaro revived this argument. In this work, we analyze the geological structure of the crustal volume affected by the seismic sequence, exploiting seismic reflection profiles and well‐log data to identify the earthquake causative fault. Our results demonstrate that the earthquake ruptured a well‐known fault of the Northern Apennines' buried thrust front, supporting that it is indeed active and seismogenic. The size and architecture of this thrust front suggest that it could generate even larger earthquakes (Mw > 6.5). This type of geological study is instrumental to understanding the geometry of earthquake faults, particularly in offshore areas, because they constitute reliable inputs for earthquake hazard models and, when done promptly after an earthquake, provide key elements for other studies on the seismic source and the unfolding of the ongoing seismic sequence. Key Points: 9 November 2022, earthquake consistent with activity of the Cornelia thrust, a fault system running off the central Adriatic coastThe seismic reflection profiles in the area allowed for delineating the thrust and its earthquake potential with a much finer resolutionThe properties of the causative fault suggest that the activation of adjacent segments is a plausible scenario that deserves consideration [ABSTRACT FROM AUTHOR]

The RETRACE-3D project (centRal italy EarThquakes integRAted Crustal model) focused on the revision of all the available geological and geophysical data in the area interested by the 2016-2018 seismic sequence of central Italy, with the final aim to reconstruct a reliable and consistent 3D geological model of that area. It is based on a collaboration, which was framed into a formal agreement, between Dipartimento della Protezione Civile (the Italian Civil Protection Department), Istituto di Geologia Ambientale e Geoingegneria, and Istituto per il Rilevamento Elettromagnetico of the Consiglio Nazionale delle Ricerche, Istituto Nazionale di Geofisica e Vulcanologia, and Istituto Superiore per la Protezione e la Ricerca Ambientale. The agreement purpose was to develop a project aimed at the geological and seismotectonic characterisation of the crustal volume hosting that seismic sequence. We present and discuss the approach, methodology and results of the project. The 3D geological model of the study area is developed in detail down to a depth of about 12 km, and extended to the Moho based on available regional-scale information. The model is available on the RETRACE-3D project website (www.retrace3d.it). [ABSTRACT FROM AUTHOR]

Fluid overpressure is a primary mechanism behind fault interaction and earthquakes triggering. The Apennines section within the young Alpine mobile belt is a key locus to investigate the interplay between fluids and faults. Here, seismicity develops along the extending mountain belt and the key role of fluids has been invoked in past large earthquake sequences. In this study, we use seismological data to get improved images of the Apennines normal faulting system, trying to catch evidences for the involvement of fluids in the preparatory phase of large earthquakes. We observe that extension preferentially reutilizes inherited fragments of faults which were assembled during the Mio‐Pliocene contraction, with steep segments that floor on a regional‐scale gently east dipping plane. We find evidences for wide volumes of overpressured fluids at the base of the seismogenic layer, which are connected to the activation of the recent large earthquakes. The recognition of fluids compartments with overpressuring and diffusion molding seismicity is a key to understand faulting processes and possibly develop forecasts scenarios. [ABSTRACT FROM AUTHOR]

The potential role of subsequent tectonic phases in reworking inherited geological structures is a key issue to unravel the seismotectonics of an area. This has a direct connection with fault segmentation, earthquakes maximum magnitude, and strong implications for seismic hazard assessment. The central Apennines (Italy) represent an exemplary case, since it developed because of the overprint of different deformational phases, producing potential conditions for episodic tectonic inversions and a very complex structural architecture. In this paper, we show how inherited compressional structures, still dominating the Apennines belt architecture, interfere with the active extension, having a direct connection with active seismotectonics. We present seismicity and new velocity tomograms of an 80‐km‐long section of the normal fault system activated during the 2009 and 2016–2018 seismic sequences. The joint interpretation highlights how the extensional seismic sequences partially reactivated inherited compressive structures, which have not an undisputable relationship with the surficial geological setting. Complexity deriving from the irregular geometry of normal faults and inverted thrust ramps is responsible for the observed intense fragmentation of the extensional system. Fluid overpressure seems to be a viable mechanism behind the partial remobilization of unbroken segments of the fault system. Key Points: Tectonic inversions and fault segmentations represent the main process behind the current crustal arrangement of central ApenninesSurface versus deep expression of faults: subsequent deformational stages cause complex interaction between inherited extensional and compressional structuresFluid overpressure plays a role in the partial remobilization of unbroken fault segments [ABSTRACT FROM AUTHOR]

Wastewater injection into a high-rate well in the Val d'Agri oilfield, the largest in onshore Europe, has induced swarm microseismicity since the initiation of disposal in 2006. To investigate the reservoir structure and to track seismicity, we performed a high-spatial resolution local earthquake tomography using 1,281 natural and induced earthquakes recorded by local networks. The properties of the carbonate reservoir (rock fracturing, pore fluid pressure) and inherited faults control the occurrence and spatiotemporal distribution of seismicity. A low- Vp, high- Vp/ Vs region under the well represents a fluid saturated fault zone ruptured by induced seismicity. High- Vp, high- Vp/ Vs bumps match reservoir culminations indicating saturated liquid-bearing zones, whereas a very low Vp, low Vp/ Vs anomaly might represent a strongly fractured and depleted zone of the hydrocarbon reservoir characterized by significant fluid withdrawal. The comprehensive picture of the injection-linked seismicity obtained by integrating reservoir-scale tomography, high-precision earthquake locations, and geophysical and injection data suggests that the driving mechanism is the channeling of pore pressure perturbations through a high permeable fault damage zone within the reservoir. The damage zone surrounds a Pliocene reverse fault optimally oriented in the current extensional stress field. The ruptured damage zone measures 2 km along strike and 3 km along dip and is confined between low permeability ductile formations. Injection pressure is the primary parameter controlling seismicity rate. Our study underlines that local earthquake tomography also using wastewater-induced seismicity can give useful insights into the physical mechanism leading to these earthquakes. [ABSTRACT FROM AUTHOR]

The geothermal resource exploration generally requires a combined analysis of various geo-information datasets. In this framework the geospatial analysis as the weighted overlay, performed under GIS (Geographic Information Systems) environment, represent a strong tool to solve problems such as the site selection. This technique is applied on not homogeneous input data to perform an integrated analysis and producing favourability maps. This work is based on the development of a new weighted overlay scheme, that combines favourable geological factors, which allow the identification of hydrothermal geothermal resources, and geological hazards (seismicity and volcanism), which can potentially limit the exploitation of a geothermal resource. The technique was tested on Tuscany Region (Italy), where two geothermal fields, Larderello-Travale/Radicondoli and Monte Amiata, are in operation. Results show that the most promising areas mostly coincide with the exploited geothermal fields. Moreover, new areas with a high geothermal favourability are identified. Low-cost and rapid resource evaluation approaches like this could play a key role during the early stages of a geothermal exploration plan. Moreover, this methodology could be extensively used in other geothermal areas not only by the scientific community but also by stakeholders, as first concrete tool to explore a potential resource suitable for exploitation. [ABSTRACT FROM AUTHOR]

The structural architecture of a portion of the eastern side of the Tyrrhenian Sea back-arc basin has been defined reinterpreting a public data set made up by seismic reflection profiles. A detailed reconstruction of the extensional front migration trough time across the area has been achieved. Migration has been defined by identifying the generation of unconformities in the graben-like basins developed in the area, as due to the activation and deactivation of normal faults. Such phenomena are part of a tectonic process that also involved blocks rotation, crustal thinning, and stretching. Syn-rift extension affected the area since the early to middle Miocene (our estimate), principally interesting the north-westernmost sectors. During late Miocene and throughout the Plio-Quaternary the extensional front moved stepwise toward the southeastern and eastern sectors. Widespread postrift conditions established over the whole area since the late Pliocene to early Pleistocene. Since the Quaternary, the locus of active extension further migrated toward the present onshore area, where a pronounced volcanic phase developed. In this evolutionary framework the rates of observed migration could be correlated with the acceleration of Calabrian slab rollback since Pliocene. Furthermore, direct evidences of magmatism were not recognized in the offshore. Although the observed crustal thinning, the absence of volcanic bodies in the study area could be related to normal faults which were unable to sufficiently extend the crust, in association with lower crust and mantle processes unable to produce melts. [ABSTRACT FROM AUTHOR]

Abstract: One of the most promising options to stabilize and reduce the atmospheric concentration of greenhouse gases is Carbon Capture and Storage (CCS). This technique consists of separating CO2 from other industrial flue gases and storing it in geological reservoirs, such as deep saline aquifers, depleted oil and/or gas fields, and unminable coal beds. A detailed reworking of all available Italian deep-drilling data was performed to identify potential storage reservoirs in deep saline aquifers. Data were organized into a GIS geo-database containing stratigraphic and fluid chemistry information as well as physiochemical characteristics of the geological formations. Caprock efficiency was evaluated via numerical parameterization of rock permeabilities, defining the “Caprock Quality Factor” (Fbp) for each well. The geo-database also includes strategic information such as the distribution of deep aquifers, seismogenic sources and areas, seismic events, Diffuse Degassing Structures, heat flow, thermal anomalies, and anthropogenic CO2 sources. Results allow the definition of potentially suitable areas for future studies on CO2 geological storage located in the fore-deep domains of the Alps and Apennines chains, where efficient marly-to-clayish caprocks lie above deep aquifers hosted in sands or limestones. Most of them are far form seismogenic sources and Diffuse Degassing Structures. [Copyright &y& Elsevier]

Since 2006 wastewater has been injected below the Val d'Agri Quaternary basin, the largest on-land oilfield in Europe, inducing micro-seismicity in the proximity of a high-rate injection well. In this study, we have the rare opportunity to revise a massive set of 2D/3D seismic and deep borehole data in order to investigate the relationship between the active faults that bound the basin and the induced earthquakes. Below the injection site we identify a Pliocene thrusts and back-thrusts system inherited by the Apennines compression, with no relation with faults bounding the basin. The induced seismicity is mostly confined within the injection reservoir, and aligns coherently with a NE-dipping back-thrust favorably oriented within the current extensional stress field. Earthquakes spread upwards from the back-thrust deep portion activating a 2.5-km wide patch. Focal mechanisms show a predominant extensional kinematic testifying to an on-going inversion of the back-thrust, while a minor strike-slip compound suggests a control exerted by a high angle inherited transverse fault developed within the compressional system, possibly at the intersection between the two fault sets. We stress that where wastewater injection is active, understanding the complex interaction between injection-linked seismicity and pre-existing faults is a strong requisite for safe oilfield exploitation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Proposal of a methodology to evaluate the energy potential of the underground. [•] Encourage a synergic use of different energy resources. [•] Development of energy-mix scenarios, considering CO2, CH4 geological storage and geothermal energy. [•] Results show that a synergic use of the underground improves the energy autonomy. [•] CO2, CH4 geological storage and geothermal energy may significantly contribute to the CO2 emissions reduction. [ABSTRACT FROM AUTHOR]

Despite the exponential increase of studies on plastic debris in recent years, there are still few works focusing on the problem as it relates to inland waters: little is known about the accumulation and dispersion dynamics on lake shores, and there are no standardized sampling methods for monitoring purposes. The accumulation of plastic litter in natural habitats also threatens the resident organisms. In this paper, we investigated the abundance and accumulation of plastic particles, ranging in size from 1 to 50 mm, from the beach sediment of three volcanic lakes in Central Italy: Albano, Bracciano, and Vico. The collection was designed to define the most important variables that one must consider in order to obtain a representative sample of plastic litter in a lake environment. In view of the high heterogeneity of sampling protocols used, comparison among the obtained results is limited and sometimes impossible. By using one of the proposed sampling methodologies, and critically analyzing the results, we aimed to highlight a possible monitoring criterion and to identify specific elements that can be meaningful and representative. The samples were collected in May and September 2017. For each lake, we sampled plastic items and sediments from two beaches. Albano contained the largest amount of plastic (in weight), while Bracciano had the largest number of particles. Our observations lead us to infer that the number of particles is the parameter most sensitive to environmental variations, as well as the more suitable for monitoring with greater definition the differences between sites. Moreover, sampling should be taken in different seasons, following a sampling pattern that includes at least two beaches placed in strategic positions with respect to wind and waves.In order to identify new indicators to evaluate the entry points of plastic into the food web, we collected, from the same sites analyzed, some specimens of the Talitrid Amphipod Cryptorchestia garbinii, a detritivorous species having a critical role in debris turnover of these environments. To investigate the microplastic (MP) ingestion in natural conditions, we analyzed their digestive tracts with both Nile red staining method and micro-FTIR spectroscopy. The analyses confirmed that C. garbinii was able to ingest plastics in natural conditions. Therefore, it can signify one of the entry points for microplastics (MPs) in the trophic chain. This observation constitutes the first evidence of MP ingestion in this species.

Studying transcription machinery assembly in vitro is challenging because of long intrinsically disordered regions present within the multi-modular transcription factors. One example is alcohol dehydrogenase repressor 1 (Adr1p) from fermenting yeast, responsible for the metabolic switch from glucose to ethanol. The role of each individual transcription activation domain (TAD) has been previously studied, but their interplay and their roles in enhancing the stability of the protein is not known. In this work, we designed five unique miniAdr1 constructs containing either TADs I-II-III or TAD I and III, connected by linkers of different sizes and compositions. We demonstrated that miniAdr1-BL, containing only PAR-TAD I+III with a basic linker (BL), binds the cognate DNA sequence, located in the promoter of the ADH2 (alcohol dehydrogenase 2) gene, and is necessary to stabilize the heterologous expression. In fact, we found that the sequence of the linker between TAD I and III affected the solubility of free miniAdr1 proteins, as well as the stability of their complexes with DNA. miniAdr1-BL is the stable unit able to recognize ADH2 in vitro , and hence it is a promising tool for future studies on nucleosomal DNA binding and transcription machinery assembly in vitro ., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

The basis for the choice of translational position of a histone octamer on DNA is poorly understood. To gain further insights into this question we have studied the translational and rotational settings of core particles assembled on a simple repeating 20 bp positioning sequence. We show that the translational positions of the core particles assembled on this sequence are invariant with respect to the DNA sequence and occur at 20 bp intervals. Certain modifications of the original sequence reduce the spacing of possible dyads to 10 bp. At least one of these alters both the translational and rotational settings. We conclude that the translational position of a core particle is specified by sequence determinants additional to those specifying rotational positioning. The rotational settings on either side of the dyads of core particles assembled on the wild-type and a mutant sequence differ by +2 bp, corresponding to an overall helical periodicity of approximately 10.15 bp. The average helical periodicity of the central two to four turns is 10.5-11 bp whilst that of the flanking DNA is closer to 10 bp. The DNA immediately flanking the dyad is also characterised by a more extensive susceptibility to cleavage by hydroxyl radical., (Copyright 2001 Academic Press.)

Although the crystal structure of nucleosome core particle is essentially symmetrical in the vicinity of the dyad, the linker histone binds asymmetrically in this region to select a single high-affinity site from potentially two equivalent sites. To try to resolve this apparent paradox we mapped to base-pair resolution the dyads and rotational settings of nucleosome core particles reassembled on synthetic tandemly repeating 20 bp DNA sequences. In agreement with previous observations, we observed (1) that the helical repeat on each side of the dyad cluster is 10 bp maintaining register with the sequence repeat and (2) that this register changes by 2 bp in the vicinity of the dyad. The additional 2 bp required to effect the change in the rotational settings is accommodated by an adjustment immediately adjacent to the dyad. At the dyad the hydroxyl radical cleavage is asymmetric and we suggest that the inferred structural asymmetry could direct the binding of the linker histone to a single preferred site.

The HMG domains of the chromosomal high mobility group proteins homologous to the vertebrate HMG1 and HMG2 proteins preferentially recognize distorted DNA structures. DNA binding also induces a substantial bend. Using fluorescence resonance energy transfer (FRET), we have determined the changes in the end-to-end distance consequent on the binding of selected insect counterparts of HMG1 to two DNA fragments, one of 18 bp containing a single dA(2) bulge and a second of 27 bp with two dA(2) bulges. The observed changes are consistent with overall bend angles for the complex of the single HMG domain with one bulge and of two domains with two bulges of approximately 90-100 degrees and approximately 180-200 degrees, respectively. The former value contrasts with an inferred value of 150 degrees reported by Heyduk et al. (1) for the bend induced by a single domain. We also observe that the induced bend angle is unaffected by the presence of the C-terminal acidic region. The DNA bend of approximately 95 degrees observed in the HMG domain complexes is similar in magnitude to that induced by the TATA-binding protein (80 degrees), each monomeric unit of the integration host factor (80 degrees), and the LEF-1 HMG domain (107 degrees). We suggest this value may represent a steric limitation on the extent of DNA bending induced by a single DNA-binding motif.

Linker histones are a major determinant of chromatin condensation. We discuss here the nature and position of the interaction of the globular domain of histone H5 with the core nucleosome and the relevance of this positioning to chromatin structure and the regulation of transcription of the Xenopus borealis 5S rRNA genes.

In Xenopus somatic cells histone H1 effects the transcriptional repression of oocyte type 5 S RNA genes, without altering the transcription of the somatic type 5 S RNA genes. Using an unambiguous nucleosome mapping method we find substantial differences between the multiple in vitro nucleosome positions on the two types of genes. These nucleosome positions determine both transcription factor and H1 binding, allowing TFIIIA to bind more efficiently to nucleosomes containing the somatic 5 S RNA gene than to nucleosomes on the oocyte 5 S RNA gene. Significantly, in a binding competition between TFIIIA and H1, TFIIIA preferentially binds to the somatic nucleosome whereas H1 preferentially binds to the oocyte nucleosome, excluding TFIIIA binding. These results strongly suggest that nucleosome positioning plays a key role in the regulation of transcription of 5 S RNA genes and provide a molecular mechanism for the selective repression of the oocyte 5 S RNA genes by H1., (Copyright 1998 Academic Press.)

To investigate the nature of the chemical determinants in DNA required for nonspecific binding and bending by proteins we have created a novel DNA in which inosine-5-methylcytosine and 2, 6-diaminopurine-uracil base pairs are substituted for normal base pairs in a defined DNA sequence. This procedure completely switches the patterns of the base pair H bonding and attachment of exocyclic groups. We show that this DNA binds a histone octamer more tightly than normal DNA but, surprisingly, does not alter the orientation of the sequence on the surface of the protein. However, in general, the addition or removal of DNA exocyclic groups reduces or increases, respectively, the affinity for the histone octamer. The average incremental change in binding energy for a single exocyclic group is approximately 40 J/mol. The orientation of the DNA in core nucleosomes also is sensitive to the number and nature of the exocyclic groups present. Notably, substitution with the naturally occurring cytosine analogue, 5-methylcytosine, shifts the preferred rotational position by 3 bp, whereas incorporating 2,6-diaminopurine shifts it 2 bp in the opposite direction. These manipulations potentially would alter the accessibility of a protein recognition sequence on the surface of the histone octamer. We propose that exocyclic groups impose steric constraints on protein-induced DNA wrapping and are also important in determining the orientation of DNA on a protein surface. In addition, we consider the implications of the selection of A-T and G-C base pairs in natural DNA.

The effects of the rotational information of DNA in determining the in vivo localization of nucleosomal core particles (ncps) have been studied in the Saccharomyces cerevisiae 5 S rRNA repeat gene. The distribution of the phased series of flexibility signals present in this DNA has been altered by inserting in its centre a 25 bp tract. The effects of such alteration on the in vivo distribution of the helically phased, alternatively located ncps have been determined relative to a reference 21 bp insertion mutant. The results show that the answers provided in vitro and in vivo by the yeast 5 S rRNA gene sequence to specific modifications of the DNA rotational frame are similar, thus pointing to the relevance of DNA rotational information in vivo.

The effects of the rotational information of DNA in determining the in vitro localization of nucleosomal core particles (ncps) have been studied in the Saccharomyces cerevisiae 5S rRNA repeat gene. We have altered the distribution of the phased series of flexibility signals present on this DNA by inserting a 25-bp tract, and we have analyzed the effects of this mutation on the distribution and on the frequencies of ncps, as compared with the wild type and a reference 21-bp insertion mutant. The variation of the standard free energy of nucleosome reconstitution was determined. The results show that the DNA rotational information is a major determinant of ncps positioning, define how many rotationally phased signals are required for the formation of a stable particle, and teach how to modify their distribution through the alteration of the rotational signals.

Several simple proteins and complex protein systems exist which do not recognize a defined sequence but--rather--a specific DNA conformation. We describe experiments and principles for two of these systems: nucleosomes and eukaryotic DNA topoisomerase I. Evidences are summarized that describe the effects of negative DNA supercoiling on nucleosome formation and the influence of DNA intrinsic curvature on their localization. The function of the DNA rotational information in nucleosome positioning and in the selection of multiple alternative positions on the same helical phase are described. This function suggests a novel genetic regulatory mechanism, based on nucleosome mobility and on the correlation between in vitro and in vivo positions. We observe that the same rules that determine the in vitro localization apply to the in vivo nucleosome positioning, as determined by a technique that relies on the use of nystatin and on the import of active enzymes in living yeast cells. The sensitivity of DNA topoisomerase I to the topological condition of the DNA substrate is reviewed and discussed taking into account recent experiments that describe the effect of the DNA tridimensional context on the reaction. These topics are discussed in the following order: (i) Proteins that look for a consensus DNA conformation; (ii) Nucleosomes; (iii) Negative supercoiling and nucleosomes; (iv) DNA curvature/bending and nucleosomes; (v) Multiple positioning; (vi) Multiple nucleosomes offer a contribution to the solution of the linking number paradox; (vii) Rotational versus translational information; (viii) A regulatory mechanism; (ix) DNA topoisomerase I; (x) DNA topoisomerase I and DNA supercoiling: a regulation by topological feedback; (xi) DNA topoisomerase I and DNA curvature; (xii) The in-and-out problem in the accessibility of DNA information; (xiii) The integrating function of the free energy of supercoiling.

A simple no-background assay was developed for high-resolution in vivo analysis of yeast chromatin. When applied to Saccharomyces cerevisiae 5S rRNA genes (5S rDNA), this analysis shows that nucleosomes completely cover this chromosomal region, occupying alternative positions characterized by a unique helical phase. This supports the notion that sequence-intrinsic rotational signals are the major determinant of nucleosome localization. Nucleosomal core particles reconstituted in vitro occupy the same positions and have the same helically phased distribution observed in vivo, as determined by mapping of exonuclease III-resistant borders, mapping by restriction cleavages, and by DNase I and hydroxyl-radical digestion patterns.

Recently, we have found that the assembly of nucleosomes reconstituted on negatively supercoiled DNA is cooperative. In the present paper the role of DNA topology and of histone tails in nucleosome assembly was explored. Reconstituted minichromosomes on relaxed DNA at different histone/DNA ratios (R) were assayed by topological analysis and electron microscopy visualization. Both methods show a linear relationship between average nucleosome number (N) and R. This suggests that in the case of relaxed DNA, cooperative internucleosomal interactions are small or absent. The influence of histone tails in nucleosome assembly was studied on minichromosomes reconstituted with trypsinized histone octamer on negatively supercoiled DNA by topological analysis. The topoisomers distribution, after trypsinization, dramatically changes, indicating that nucleosome-nucleosome interactions are remarkably decreased. These results show that, in chromatin folding, in addition to the well known role of histone H1, the interactions between histone octamer tails and DNA are also of importance.